To DFT calculations [1]}, [2]} the electrons (without impurity) are considered as noninteracting in their plane-wave Kohn-Sham one-electron states. The momentum distribution
function of them is an ideal Fermi-Dirac distribution with (invariant) Fermi surface defined from the density \(n_0\) . However, as many-body methods [3]}, [4]}, [5]} indicate, the excitation spectrum above such a
surface may get modulations (due to dynamical exchange-correlation
[6]} between electrons) beyond the one prescribed by the imaginary part
of the noninteracting (\(m^{*}=m\) ) density-density response function
[which is \(\propto {\omega }\) , independently of the characteristics (\(v_F\) ) of the filled ground-state],
i.e., of the Lindhard function of the time-dependent linearized Hartree-type approximation for screening. In [7]} we made an attempt to combine static screening nonlinearities with many-body modulation
in the electron-hole excitation spectrum (which should depends on \(m^{*}\) , according to Landau's physics-based [3]}, [5]} intuitive treatment)
responsible for dissipation. Only small changes in stopping, depending slightly on \(Z_1\in {[5,40]}\) , were observed in [10]} for an electron gas with \(r_s=2\) .
